Fingerprint and palmprint image collectors are currently used in a growing number of fields, such as mobile phone, tablet, television and other electronic terminals, as well as various security systems. With the development trend of ultra-thin electronic terminals, higher requirements are raised naturally for the volume, thickness of an image collector integrated in the electronic terminal and the definition of acquired images thereof, and the like.
The existing fingerprint image collector, such as a thin type optical fingerprint acquisition device disclosed in Chinese Patent Application NO. 201120403301.0, generally includes an image acquisition prism, an imaging apparatus and an image processing element. The imaging apparatus further includes a lens, a photoelectric signal conversion circuit, a digital processor and the like. A relatively long light path is required to meet the requirement for light imaging, because the image acquisition prism is used as an acquisition component for light, and the lens is required to complete the light imaging of fingerprint. The image scanner must have a relatively large volume and thickness to implement the acquisition of a fingerprint image, due to a relatively large volume and thickness of the image acquisition prism and the lens, as well as factors such as the length of light path. In addition, it is difficult for the existing image scanner to meet requirements of various electronic terminals for low cost, small volume and ultra-thinness of the image collector, due to the high cost and complex structure caused by associated components such as the image acquisition prism and the lens.
Therefore, how to reduce the thickness of the optical fingerprint acquisition apparatus becomes a technical problem to be solved.